Arc-lamp.



M. FORTUNY.

ARC LAMP.

APYLIGATION FILED JAN. 10, 1906.

948,971 Patented Feb. 8, 1910.

WITNESSES NVENTOR :BY /w/a; @aM-Lf. ma

ATTORNEYS cause a movement of thee ectrodes.

MARIANO FORTUNY,

or' Panis, FRANCE.

ARC-LAI?.

Specification of Letters Patent.

Patented Feb. 8, 1910.

Application filed January 10, 1906. Serial No. 295,419.

To all whom it may con/cem: l

Be it known that I, MARIANO F oR'rUNY, a l subject of the King of Spain,residing at 19 Boulevard Berthier, Paris, France, decorative artist,have invented certain new and useful Improvements in Arc-Lamps, of whichthe following is a speciiication.

My invention relates to electric arc lamps, and more especially to lampsof the type in which the movements of the electrodes are produced solelyby an electric motor. In such lamps, the field magnet of thecontrollingmotor is usually provided with two differential coils, one of which isin series and the other in shunt with the voltaic arc. The operationofsuch lamps is therefore very similar to that of the ordinarydifferential arc lamp, the solenoids being replaced by the controllingmotor.

' The object of my invention is to provide proved means for regulatingthe voltaic arc, With this object in view I provide the field magnet ofmy lamp-controlling motor with three coils, one being of coarse wire`and arranged in series with the light arc, and the two others being offine wire ar ranged in shunt with the arc, 'but in series with eachother. The armature of the motor is connected from one of its brushes toav point between the two fine wire windings and from its second brush toa point in the main circuit beyond the arc. By this arrangement I obtaina greater sensitiveness of my lamp to variations of voltage and it hasbeen found by experience that a. variation of one-half volt is uitesufficient to My invention will be fully understood by reference to theaccompanying drawings, in whichw l Figure 1 represents a side elevationpartly in section,- of a lamp embodying my invention. Fig. 2 is adiagrammatic view of the circuit.

In Fig. 1 A represents the armature and B-the field magnet of thelmotor." On the' armature shaft is fixed a pinion C, which meshes withthe toothed wheel D on a shaft E. The latter is supported in suitablebearings formed on the lamp frame and is c onnected, by means of anysuitable iexible connection, for exam le the spiral spring M, with asecond sha F in line with and of the same diameter as'the shaft Theshafts E, F are screw-threaded, the threads being inverse to each other.Slidably mounted on vertical rods secured to the lamp frame are thecarbon holders G and H, to which the carbons are secured by means oflittle set-screws. The carbonholders Gr, H have inner-threaded circularportions forming the nuts for the threaded shafts E, F, so that, whenthe latter are rotated the carbon-holders are moved together orseparated from each other. The iield magnet B of the motor is U-shapedand has on each of its legs two windings Bl and B2, the former being ofline wire, the latter of coarse wire. As appears from Fig. 2, the coarsewire windings B2 are wound in the same sense and connected in such amanner that they may practically be regarded as one winding B2. The newire windings lB1 however, act sometimes in the same and sometimes in aninverse sense, as will be clearlyunderstood from the following. The maincircuit lows from the pole through the coarse wire winding B2 to pointg,'

thence through the carbons to the point p and throul h the rheostat Itto the poledso 'Between t e points g and p the line )112e windings B1are arranged, so that they are in shunt with the are, while thc/windingB2 is in series with the latter. The arma 'ture A of the motor isconnected from one of its brushes to the point m between the fine wirewindings B1, while the other brush is connected with a suitable point nupon the rheostat R.

The operation is as follows: Assuming that the electrodes are in Contactwith each other and current is switched on to the lamp. A main circuitis from the -lpole through the coil B2 to point g and through theearbons and Ithe rheostat R to the pole. A shunt circuit is establishedfrom the point g through the right hand .winding B1 to the point m andthence through the armature A to the point n by reason oi' the cut-tingout. of portion of the resistance R. As' long as the electrodes are incontact with each other, the resistance between the points g andv p iscomparatively small and the points p and g are at practically the samepotential. The point n being thus at a lower potential than the points gand p since portion `of the resistance R is cut out by the connectionfrom m to n, a third current passes from point p through the left handcoil B1 to the point m. The two windings B1 thus 4act in an inversesense, the left-hand winding aiding the action of llO the coarse wirewinding B2. The electrodes therefore are separated very quickly by therotation of the motor and the arc is formed. lVhen on the contrary, theelectrodes are separated from each other so far that the arc islengthened, then the resistance between the points g and p is soincreased and the main current consequently so decreased, that the shuntcircuit passes from g through both the fine wire windings B2 to thepoint p and the said windings B2 consequently now act in the same senseand the electrodes are again brought together.

It is evident that a point of equilibrium exists between the action ofthe three coils, which point is reached when the aro-voltage has apredetermined value. It appears further that as long as thearc-resistance is lower thaiA the resistance of the right-hand coil B1,current will flow from p to lml and the action of the coils B1 will beinverse "tid" each other and that, when the arc-resistance is greaterthan that of the rightliand winding B1, the two coils B1 will act 1n thevsame sense and reinforce each other. Having thus an auxiliary fieldmagnet coil (leftregulation than would be possible with a lamp asheretofore used having only two differential field magnet coils.

I do not limit myself to the details of construction as shown in thedrawing, but various other forms of motors and of transmission devicesbetween the motor and the electrodes may be used without departing fromthe principle of my invention.

I claim as my invention:

In a device of the character described, an electric motor, a eld magnettherefor provided with three windings, one of which is arranged inseries with the arc, and the two others in shunt with the arc but inseries with each other, in combination with a. connectionfrom a pointbetween the two windings in the shunt circuit to one of the brushes ofthe armature and a connection from the other brush of the armature to apoint in the main circuit beyond the 'arc together with a suitableresistance between said point and the arc.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses.

MARIANO F ORTUNY.

1Witnesses:

GUs'rAvE DUMONT, HANsoN C. CoXE.

